Re: How many buckets

Js wrote:
> Hello Experts,
>
> I need your comments on below topic.
>
> Oracle generating 2 buckets for each column if I am executing this
> command.
>
> SQL> analyze table t compute statistics;
>
> Table analyzed.
>
> SQL> select count(*),column_name from user_Tab_histograms where
> table_name = 'T' group by column_name;
>
> COUNT(*) COLUMN_NAME
> ---------- --------------------------------------------------
> 2 CREATED
> 2 DATA_OBJECT_ID
> 2 GENERATED
> 2 LAST_DDL_TIME
> 2 OBJECT_ID
> 2 OBJECT_NAME
> 2 OBJECT_TYPE
> 2 OWNER
> 2 SECONDARY
> 2 STATUS
> 2 SUBOBJECT_NAME
> 2 TEMPORARY
> 2 TIMESTAMP
>
> 13 rows selected.
>
> And If use this command ...
>
> SQL> analyze table t compute statistics for table for all columns;
>
> Table analyzed.
>
> SQL> select count(*),column_name from user_Tab_histograms where
> table_name = 'T' group by column_name;
>
> COUNT(*) COLUMN_NAME
> ---------- --------------------------------------------------
> 76 CREATED
> 75 DATA_OBJECT_ID
> 2 GENERATED
> 76 LAST_DDL_TIME
> 76 OBJECT_ID
> 76 OBJECT_NAME
> 24 OBJECT_TYPE
> 11 OWNER
> 1 SECONDARY
> 2 STATUS
> 2 SUBOBJECT_NAME
> 2 TEMPORARY
> 76 TIMESTAMP
>
>
> I am confused .. No of buckets is dependent upon what ?
>
> Regards.

http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_4005.htm#SQLRF01105

also: http://tahiti.oracle.com
and search for "Bucket" and "ANALYZE" together

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)